Morphine is useful as an analgesic drug. It is also used as the starting material for the preparation of codeine, which is another analgesic and antitussive drug. Morphine occurs naturally in opium to the extent of 9 to 17% by weight, depending upon the opium source.
There are many alternative methods of extracting and purifying morphine from opium. However, these methods suffer from several disadvantages, such as prolonged extraction times, low efficiencies and the involvement of hazardous chemicals such as chloroform and sulfur dioxide. What is needed is a cost-effective process which does not require large amounts of potentially toxic or hazardous solvents. When viewed from this perspective, none of the current methods are entirely satisfactory.
Generally, current methods extract the alkaloids present in opium with either water or an acidic (e.g. oxalic acid) solution. Due to the limited solubility of the alkaloids in aqueous solutions, the extract is very dilute. This results in a large amount of the aqueous extract. Recovery of the alkaloids from the aqueous extract also requires large amount of organic solvents. The process is also lengthy and labor intensive. One batch of opium generally needs to be extracted four times over a period of four days for complete recovery of the alkaloids. Separation and purification of morphine from the other alkaloids in the aqueous extract is also time consuming and relatively complicated due to the physical properties of the extract and the nature of the substances present.